How key legal decisions have shaped the politics of Brexit

The courts have played a key role in the Brexit process. While individuals and groups may have had political motives for bringing legal actions, the courts focused on determining legal issues. Nevertheless, their decisions have had political ramifications and suggest a growing role for the courts in the shaping of the UK constitution.

However, this has been in the face of criticism, particularly of the courts’ role in the Miller case, which saw the judges branded as ‘enemies of the people’. If courts are to play their proper role, politicians need to be more prepared to defend them.

The first key case was Miller. Gina Miller and others argued that the Prime Minister could not trigger the Article 50 process on her own. The Prime Minister claimed that she could use the prerogative, a power stemming from the historical authority of the Crown. The Supreme Court disagreed. The broad prerogative power to enter into and withdraw from treaties did not include a power to modify UK law, or to frustrate legislation, or to remove rights enjoyed by UK citizens.

The majority of the Supreme Court concluded that the law would be changed and legislation frustrated were Article 50 to be triggered, as this could lead to the UK leaving the EU without parliamentary authorisation. Therefore, legislation would be needed to empower the Prime Minister to trigger Article 50. Parliament could now have a say on the conditions under which the Prime Minister communicated the UK’s decision to leave the EU. Without Miller, there would have been no need for the European Union (Notification of Withdrawal) Act 2017.

However, the Supreme Court concluded that this legislation did not, legally, require the consent of the devolved legislatures. Whilst such consent may be required by the Sewel Convention, this was only a constitutional convention. Conventions are only politically, not legally binding. Thus, whilst the Sewel Convention has great constitutional significance, it is fragile in nature. It requires politicians to accept its importance to ensure good relations between Westminster and the devolved nations.

The second key case was the Scottish Continuity Bill Reference. As the European Union (Withdrawal) Bill (EU(W)B) progressed through Parliament, it became clear that there were tensions between Westminster, Scotland, and Wales concerned devolved powers. As the UK leaves the EU, powers that were exercised by the EU return to the UK, being exercised by Westminster, or the devolved legislatures and executives, according to the various devolution settlements.

The EU(W)B originally placed all of these powers in the hands of the Westminster Parliament on a temporary basis. This led both Wales and Scotland to initiate their own version of the European Union (Withdrawal) Bill – the Welsh Continuity Bill and the Scottish Continuity Bill.

The EU(W)B was then modified. Powers would be transferred to the devolved nations. But ministers in Westminster could make orders to return specific areas of power to Westminster on a temporary basis. Scotland did not accept this change. The Scottish parliament voted against giving its consent to the EU(W)B.

The UK government used the special procedure found in section 33 of the Scotland Act 1998 to challenge the Continuity Bill after its enactment in the Scottish parliament, but before it had received royal assent. The UK Supreme Court concluded that the Scottish Continuity Bill as a whole was not beyond the competence of the Scottish parliament. However, it ruled that section 17 – which required that UK ministers must obtain the consent of Scotland when enacting delegated legislation altering the powers of Scotland – fell outside the powers of the Scottish parliament. This modified section 28(7) of the Scotland Act 1998.

However, the Scottish parliament does not have the power to modify the Scotland Act 1998. The Supreme Court also concluded that provisions of the Continuity Bill would be beyond the powers of the Scottish parliament at the time the Bill would come into force. After the challenge was initiated before the Supreme Court, the EU(W)B received royal assent.

The European Union (Withdrawal) Act 2018 (EU(W)A) amended the Scotland Act 1998. It added itself to the list of legislation that the Scottish parliament was unable to modify. The Scottish Continuity Bill contained provisions which contradicted the European Union (Withdrawal) Act 1998. These provisions were ruled to be beyond the powers of the Scottish parliament.

The decision reinforced the power of Westminster over the Scottish parliament. Scotland was unable to incorporate EU law into Scottish law in a manner different from that in the UK, where this would modify the EU(W)A.

The final key case was Wightman. Andy Wightman MSP and others asked the Scottish courts to make a reference to the ECJ. They wanted to ask if it was legally possible for a member state to unilaterally revoke its notification to withdraw from the EU.

This knowledge changed the tenor of the debate in Parliament. The choice now includes leaving the EU with a deal, leaving with no deal, or revoking Article 50 and remaining in the EU. Each of these decisions influenced the Brexit debate. Yet they did not increase the powers of the court.

They reinforced the powers of Parliament. They also illustrate the limits of the courts. Miller shows that courts will not enforce conventions, which assumes there is sufficient political pressure to ensure the Sewell Convention is followed. The European Union (Withdrawal) Act 2018 was enacted without Scotland’s consent, in breach of the Sewel convention. The Scottish Continuity Bill Reference reinforces Westminster’s legal dominance over Scotland.

Brexit has taught us that the courts and Parliament can work together. But this needs Parliament as well as the courts to play their full constitutional role. It also requires Parliament to understand and support the proper constitutional role of the courts.

By Alison Young, Sir David Williams Professor of Public Law at the University of Cambridge, and a Fellow of Robinson College. This article is from our ‘Article 50 two years on’ report.

Disclaimer: The views expressed in this analysis post are those of the authors and not necessarily those of the UK in a Changing Europe initiative.